NEW YORK -- World number one and defending champion Lleyton Hewitt overcame a sluggish start to ease past Noam Okun 7-6 6-4 6-1 on Thursday and into the third round of U.S. Open.

Following a five-hour rain delay, Hewitt stepped on to the Louis Armstrong court under dull skies and was far from sharp as he struggled to find his rhythm in an error strewn opening set.

The 21-year-old Australian had looked in danger of dropping the opening set until Okun double-faulted on set point handing Hewitt the tiebreak 9-7.

Jolted into action, Hewitt continued to pick up momentum throughout the match speeding through the final set in just 27 minutes, Reuters reported.

Up next for Hewitt is America's newest tennis heartthrob, 25th seed James Blake, who reached the third round for the first time with a four sets win over Russian Nikolay Davydenko.